Chromaffin cells of the adrenal medulla are innervated by the splanchnic nerve and secrete adrenaline, noradrenaline, and enkephalin into the bloodstream. As such, they play an important role in the fight-or-flight response. They are also referred to as granules and this is where the enzyme dopamine-hydroxylase catalyzes the conversion of dopamine to norepinephrine.

What do chromaffin cells do?

secrete epinephrine (80%) and norepinephrine (20%) into the circulation

What is pheochromocytoma?

tumor of the medullary gland --> over secretion of catecholamines --> increased VMA levels (VMA is found in vanilla ice cream)

what is the NT of adrenergic neurons?

NorEpi

What is the NT of cholinergic neurons?

ACh

What are some types of nonadrenergic and noncholinergic neurons, and what do they secrete?

Jacksonian seizures are initiated with abnormal electrical activity within the primary motor cortex. They are unique in that they travel through the primary motor cortex in succession, affecting the corresponding muscles, often beginning with the fingers. This is felt as a tingling sensation. It then affects the hand and moves on to more proximal areas. Symptoms often associated with a Jacksonian seizure are sudden head and eye movements, tingling, numbness, smacking of the lips, and sudden muscle contractions. Most of the time any one of these actions can be seen as normal movements, without being associated with the seizure occurring. They occur at no particular moment and last only briefly.

What is the function of white fat?

Most adipose tissue is white, the focus of this review. White adipose tissue serves three functions: heat insulation, mechanical cushion, and most importantly, a source of energy.

What is the function of brown fat?

Its primary purpose is to generate body heat. In contrast to white adipocytes (fat cells), which contain a single, large fat vacuole, brown adipocytes contain several smaller vacuoles and a much higher number of mitochondria. Brown fat also contains more capillaries since it has a greater need for oxygen than most tissues.

What are the three divisions of the autonomic nervous system?

1. sympathetic
2. parasympathetic
3. enteric

What are the two nervous system branches?

1. autonomic nervous system
2. somatic nervous system

Where are the preganglionic neurons of the sypathetic nervous system found?

T1-L3

Where are the preganglionic neurons of the parasympathetic NS found?

- nuclei of cranial nerves
- S2-S4

IS the Adrenal medulla a ganglion of the sympathetic or parasympathetic NS?

more sensitive to epi than to norepi
more sensitive to epi than a1 receptors

What is the mechanism of action of B2 receptors?

Gs protein stimulates adenylate cyclase and increases cAMP

Where are nicotinic receptors found?

- autonomic ganglion
- neuromuscular junction
- adrenal medulla

What are nicotinic receptors activate by?

- Ach
- nicotine

What are the actions of nicotonic receptors?

- activation
- binds to alpha subunit and allows passage of Na and K

What are nicotinic receptors blocked by?

- ganglionic blockers (hexamethonium)

What is hexamethonium?

Hexamethonium is an nAch receptor antagonist which acts in autonomic ganglia by preventing the acetylcholine molecules from binding to the site of the cholinergic receptor. It has no effect on the muscarinic acetylcholine receptors, or mAChRs.

Where does hexamethonium act?

at the autonomic ganglia, but not at the neuromuscular junction

Name the types of muscarinic receptors and where they're found

M2: heart
M3: smooth muscle and glands

How do muscarinic receptors act in the heart?

are inhibitory:
decreased HR
decreased condiction velocity in AV node

How do muscarinic receptors act at the smooth muscle and glands?

excitatory:
- increased GI motility
- increased secretion

What activates muscarinic receptors?

ACh and muscarine

What blocks muscarinic receptors?

atropine

How do muscarinic receptors act on the Heart?

AT the SA node, Gi protein inhibits adenylate cyclase, whcih leads to opening of the K+ channels. This slows the rate of spontaneous Phase 4 depolarization and decreases heart rate